update reverse linked list

Author: jylee2033

reverse-linked-list/jylee2033.py

@@ -6,22 +6,22 @@
 class Solution:
     def reverseList(self, head: Optional[ListNode]) -> Optional[ListNode]:
         # Handle empty list
-        if head is None:
-            return head
+        # if head is None:
+        #     return head
 
         prev = None
         cur = head # Start from the head node
 
         # Traverse until the last node
-        while cur.next is not None:
+        while cur is not None:
             nxt = cur.next # Store next node
             cur.next = prev # Reverse the link
             prev = cur # Move prev forward
             cur = nxt # Move cur forward
 
         # Handle the last node
-        cur.next = prev
-        return cur
+        # cur.next = prev
+        return prev
 
 # Time Complexity: O(n)
 # Space Complexity: O(1)